FOR THE FILLING:

6 tbsp. chopped walnuts or pecans
2 c. milk
1/2 c. sugar
Pinch of baking soda
1 (2-inch) cinnamon stick
1/2 tsp. vanilla extract

FOR THE COOKIES:

5 egg yolks
1 1/2 tsp. sugar
2 tbsp. butter
1/2 tsp. Pisco liquor, or brandy, or rum
1 c. flour
3 tbsp. confectioners sugar

The Filling: Chop the nuts very finely. Combine in a saucepan the milk, sugar, baking soda and cinnamon stick. Place over medium heat and cook, stirring constantly, until mixture begins to boil. Turn heat down to low immediately and simmer gently for 1 hour and 30 minutes, or until the mixture becomes as thick as very heavy cream and brownish in color. Stir it about every 10 minutes while it cooks.

When thick, remove from heat and allow to cool for 10 minutes. Remove cinnamon stick. Stir in vanilla. Let filling sit until completely cool. It will get thicker as it cools. Stir in nuts. If you aren't making the cookies right away, spoon the filling into a glass jar, cover tightly with a lid, and store in the refrigerator.

To make the cookies, separate 5 eggs. Put the whites in a bowl and save for another use. Put yolks in a mixing bowl and beat well with an egg beater. Add sugar and beat again.

Preheat oven to 350 degrees. In a small saucepan melt the butter over a very low flame. Remove from heat and add, a little at a time, to the egg yolk mixture, beating each time with the egg beater. Add the Pisco liquor or brandy or rum, and stir with a spoon.

Onto a piece of waxed paper sift the flour. Measure and sift again gradually, into the egg mixture, mixing well each time.

Sprinkle a little flour on a pastry board and with a floured rolling pin roll out the dough as thin as you can roll it. Cut out cookies with the round cookie cutter. Lift away extra dough.

If your cookie cutter does not have a fancy edge, then go around the edge of each cookie with a fork to make fancy marks. Arrange the cookies on ungreased baking sheets and bake 7-9 minutes. Do not let the cookies get brown. Remove from oven and baking sheets and cool on wire rack.

With a table knife, spread some of the cooled filling on half of the cookies. Put the remaining cookies on top to make sandwiches. Sift confectioners sugar over the cookie sandwiches. Makes about 1 1/2 dozen.